﻿// Copyright (c) 2008 MySQL AB, 2008-2009 Sun Microsystems, Inc.
//
// MySQL Connector/NET is licensed under the terms of the GPLv2
// <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most 
// MySQL Connectors. There are special exceptions to the terms and 
// conditions of the GPLv2 as it is applied to this software, see the 
// FLOSS License Exception
// <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
//
// This program is free software; you can redistribute it and/or modify 
// it under the terms of the GNU General Public License as published 
// by the Free Software Foundation; version 2 of the License.
//
// This program is distributed in the hope that it will be useful, but 
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 
// for more details.
//
// You should have received a copy of the GNU General Public License along 
// with this program; if not, write to the Free Software Foundation, Inc., 
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace MySql.Data.Entity
{
    class Scope
    {
        private Dictionary<string, InputFragment> scopeTable = new Dictionary<string, InputFragment>();

        public void Add(string name, InputFragment fragment)
        {
            scopeTable.Add(name, fragment);
        }

        public void Remove(InputFragment fragment)
        {
            if (fragment == null) return;
            if (fragment.Name != null)
                scopeTable.Remove(fragment.Name);

            if (fragment is SelectStatement)
                Remove((fragment as SelectStatement).From);
            else if (fragment is JoinFragment)
            {
                JoinFragment j = fragment as JoinFragment;
                Remove(j.Left);
                Remove(j.Right);
            }
            else if (fragment is UnionFragment)
            {
                UnionFragment u = fragment as UnionFragment;
                Remove(u.Left);
                Remove(u.Right);
            }
        }

        public InputFragment GetFragment(string name)
        {
            if (!scopeTable.ContainsKey(name))
                return null;
            return scopeTable[name];
        }
    }
}
